An idealized geometry of the infant nasal airways is developed with the goal of mimicking the average inertial filtration of aerosols by the nasal passages. Paramount geometrical features of 10 previously published nasal replicas of infants aged 3-18 months have been considered in creating the idealized version. Simplifications are made to features that do not significantly influence deposition but that make the airway unnecessarily convoluted. A series of overall deposition measurements have been carried out in the idealized replica over a range of particle sizes and breathing patterns. Deposition data for the idealized geometry are compared with those from 10 in vitro subjects. Satisfactory agreement between deposition in the idealized and real geometries suggests that the idealized version can characterize average deposition in the real airways. The present idealized airway could be useful as a reference geometry in experimental and theoretical studies of aerosol delivery through infant nasal airways. (C) 2012 Elsevier Ltd. All rights reserved.